Testing device for determining the viscosity of rubber



R. B. NAYLOR. TESTING DEVICE FOR DETERMINING-THE VISCQSITY 0F RUBBER.

APPL ICATION FILED FEB. 5, 1919.

Patented Jan. 13, 1920.

ATTORNEYS.

' UNITED sTAT s PATENT omen.

RALPH B. NAYLOB, OF SPRINGFIELD, MASSACHUSETTS, ASSIGNQR TO THE FISK RUBBER COMPANY, OF CHICOPEE' FALLS, MASSACHUSETTS, A CORPORATION 4 OF MASSACHUSETTS.

I 'r ss'rme DEVICE FOR DETERMINING THE VISCOSITY or RUBBER.

To all whom it may concern:

Be it known that I, RALPH B. Name, a citizen of the United States of America, residing at Springfield, in the county of Hampden and State of Massachusetts,

ed certain new and useful Improvements in Testin Devlces for Determining the Viscosity of ubber, of which the following is a specification. A

The present invention relates toa testing device for determining the v1scosity o f rubber, and has for its object the PI'OVlSlOIl of a mechanism for determining the viscosity under varying conditions of .temperature and pressure.

Referring to the drawings:

' Figure 1 is a side elevation of the device,

inder.

partly in section; and

Fig. 2 is a plan view of the lower gripping member.

A cylinder 10 is secured by means-of a bracket 11 to table 12. The cylinder is cored out as at 13 and provision is made 'for the circulation of'steam or other heating medium by tapped holes 14; and 15, or the cylinder may be heated in any other well known way, as by electrical resistance coils. To keep track'of the temperature at all times a thermometer may be inserted at 16.

A hole 17 runs axially through the cylinder, and is widened at its lower end for the reception of a nut 18, which screws into place. his nut carries, fastened to it against rotation, a lower gripping member Directly above pulley 26, which is keyed at 27 to shaft 24. A cord 28 is fastened to the pulley 26- and, after passing around the latter, runs over a second pulley 29 mounted on a bracket 30 on the side of the cylinder. -To the end of cord 28 is attached a plate 31, on which may have inventa to the pulley 26 and of the pointer before each reading, pointer the cylinder is a grooved- Specification of Letters Patent. Patented J 3,11, 13, 1920, Application filed February 5, 1919. Serial No. 275,154. Y

be placed different weights be changed to produce any desired torsion on shaft 24 through the mediumof cord 28 and pulley'26. 33 may be placed over an extension 34: of shaft 24, and rest on pulley 26, thereby giving control over the pressure with which the upper grlpping member is forced downwardly. To indicate the amount of rotation of the upper gripping member relative to the lower member a pointer 35 is attached runs over a scale 36 on the side of cylinder 10. To facilitate reading of "the scale by allowing a zero setting is secured to a bolt 37 passing through an arcuate slot intlie pulley 26. The pointer may be clamped in any desired position by a thumb nut 38.

In testing the viscosity my device nut 18 rubber is laid on, top of the lower gripping member and the nut screwed back into place. Steam is admittedto chamber 13 until the rubber has had an opportunity to be uniformly heated to the Weights 32 and 33 are then placed in posiof rubber with tion. The travel of pointer 35 during a definlte. period of time Is noted and serves as the basis for the comparison of various rubber stocks.

Stocks of a certain grade should show a definite travel for known conditions of pressure, torsion, temperature and time, and, these being known for standard stocks, a

comparison of samples is. easy. It will be understood that the lower face of the test piece of rubber laid on gripping member 19 is held by this stationary gripping member while the movable gripping member 23 causes a movement of the rubber proportioned to its viscosity under the conditions of the test. It is the viscosity of the'rubber which permits the larger part of the movement indicated on the scale.

A further use of this device is in rect determination of the coefficient of viscosity. A calibration chart can be prepared, showingthe coeflicient of viscosity corresponding to difi'erent amounts of travel of the pointer in a unit time for diife'rent conditions of pressure, torsion and temperature,

and, those conditions being known and the 32, which may Another set of weights the is removed, a test piece of desired temperature.

the ditravel of the pointer determined, the coeflicient of viscosity for'the sample inhand may be read directly from the chart Having thus described my invention, 1 claim? r 1. In a testing device of the class de-' scribed opposing gripping me-mbers for holding a test piece of rubber, and adapted for relative rotation about an axis perpen-' dicular to the general plane of their grip ping surfaces, means for causing a known pressure between the members, means for causing a, known torsion between the members, and means for indicating the resulting amount of relative rotation between the members,

2. In a testing device of the, class described, opposing gripping membersfor holding a test piece of rubber, and adapted for relative rotation aboutan axis perpendicular to the general plane of their grip-- 3. In a device of the class de-- scribed,

oppos ng gripping members for holding a test pieceof rubber, and adapted for relative rotation-about an axis perpem' dicular to the general plane of thelr grippmg surfaces, means whereby varying degrees of torsion may be exerted between the members, and means for md catmg the reholding a ping surfaces,

suiting amount of relative rotation between the members.

4. In a. testing device of the class described, opposlng gripping members {for dicular to the general plane of their gripmeans whereby varying degrees of torslon may be exerted between-the members, means for indicating the resulting" amount of relative rotation between the members, and means for heating theltest P fl 1 7 V 5. In a testing device of the class detest piece of rubber,and adapted for relative rotation about anaxis perpen-,

scribed, a stationary gripping 'member, a-

shaft in axial alinement 'wlth said gripping member, a second grippingmember-secured the pressure beto' the shaft, means whereby gripping members may be tween the two.

regulateduand held constant, means for rotating the shaft with a known torsion, and means for applying heat to a test piece of rubber held'between the gripping members.

6.- In a testing device of the class described; a stationary gripping member; a shaft in axial alinement withsaid gripping member, said shaft being constructed and arranged for the reception of weights, whereby the shaft may be forced .withregulable and known premure toward said gripping member; a second gripping member fast to the shaft; and a pulley on the shaft, and regulable weight means connected to' the. pulley, whereby the shaft may be impelled to rotate with a regulable and known torsion.

RALPH B. N AYLOR. 

